fix: properly access release please output for artifact upload (#156)

.github/workflows/release-please.yml

@@ -60,8 +60,8 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         with:
-          upload_url: ${{ github.event.release.upload_url }} # This pulls from the CREATE RELEASE step above, referencing it's ID to get its outputs object, which include a `upload_url`. See this blog post for more info: https://jasonet.co/posts/new-features-of-github-actions/#passing-data-to-future-steps 
+          upload_url: ${{ steps.release.outputs.upload_url }} # This pulls from the CREATE RELEASE step above, referencing it's ID to get its outputs object, which include a `upload_url`. See this blog post for more info: https://jasonet.co/posts/new-features-of-github-actions/#passing-data-to-future-steps 
           asset_path: ./slides.zip
           asset_name: slides.zip
-          asset_content_type: slide/zip          
+          asset_content_type: slide/zip 
           #      - name: Upload Release Artifacts